How to increase Firetube boiler efficiency by 45 % or more by Etienne Fourie , Technical Sales Manager , Babcock Wanson
BOILERS & MAINTENANCE INDUSTRIAL PROCESS HEATING EQUIPMENT
BABCOCK WANSON
How to increase Firetube boiler efficiency by 45 % or more by Etienne Fourie , Technical Sales Manager , Babcock Wanson
There ’ s no denying that process heating systems are large consumers of energy . With sky high energy prices to contend with and Net Zero on the horizon , efforts to reduce energy consumption , improve efficiency and reduce emissions are centre stage . When it comes to Firetube boilers , manufacturers of these systems have been working hard to improve overall efficiency and control of boilers and burners . Here we look at the key developments that , combined , could increase your Firetube boiler efficiency by 45 % - a substantial figure .
Variable Speed Drive Electric motors used on boiler feed pump and combustion air blowers traditionally operate at a constant speed . However , boilers are rarely operated continually at full capacity , so maintaining the motor at the same speed at all times is wasteful . Where process load demands are variable , motors can be fitted with a variable speed drive ( VSD ) which can increase efficiency by up to 30 % ( based in reduced electrical consumption ).
A VSD is an electronic device used to adjust the rotation speed of an electric motor according to the needs of the application . In a Firetube boiler they can be used to vary the pump or fan speed according to demand , ramping up or down the frequency and voltage to the motor , reducing overall energy consumption .
A further benefit to be had from the use of a VSD is equipment longevity . The inherent soft-start function of a VSD , means the motor starting current can be reduced , which decreases thermal and mechanical stresses .
Flue Gas & Condensing Economisers Economisers are essentially heat exchange devices that extract the residual heat from the exhaust gas generated by the combustion process . That recovered heat is usually fed back into the process , typically to the boiler feed water thereby optimising the overall efficiency of the plant in the most compact and cost-effective manner .
By using economisers , you can expect to increase efficiency of your Firetube boiler by 15-20 %. Babcock Wanson offers a broad range of exhaust gas economisers perfectly matched to the boiler to which they will be fitted , incorporating ultra-robust extended surface tubes , which ensure the best practicable heat transfer and allow boiler thermal efficiencies of 98 % and greater to be achieved . So efficient are they , that the return on investment can be as little as a single year .
Different types of economisers are available to meet a wide variety of processes and site needs , including economisers that can be mounted in a drawer in the back box of the boiler and those suitable for mounting in casing on the smoke outlet , plus economisers with feed water exchanger , and those that come with fumes / water / combustion air exchanger .
50 PECM Issue 72